Method for managing communication network, and communication device

ABSTRACT

The invention provides a method of managing a network in which the configuration of communication devices can be freely modified and each terminal can operate as a hub terminal for controlling the network, and a communication device. Following network management information transmitted by the hub terminal periodically, each leaf terminal transmits terminal synchronization information and then transmits data. The network management information includes network ID retained by the hub terminal, station ID information in the form of information indicating the use/non-use of station ID in the network, and a terminal synchronization information transmission request which designates the leaf terminal which should transmit a terminal synchronizing signal. The leaf terminals designated by the terminal synchronization information transmission request transmit the individual terminal synchronization information sequentially following the network management information.

FIELD OF THE INVENTION

[0001] The present invention relates to a network of a single hubterminal and other leaf terminals in communication with one another.Particularly, the invention relates to such a network in which each of aplurality of communication devices existing in the network can be a hubterminal, and that the configuration of the communication devices in thenetwork can be modified as desired.

BACKGROUND OF THE INVENTION

[0002] Normally, in a network that requires a hub terminal, the hubterminal is a fixed base station or other specific terminal wherenetwork control information is locally retained.

[0003] JP Patent Publication (Unexamined Application) No. 10-13440discloses a means of modifying the terminal configuration in a network.JP Patent Publication (Unexamined Application) No. 7-203535 discloses ameans of changing the hub terminal dynamically in a network of aplurality of terminals.

[0004] When the terminal configuration of a network is modified, thenetwork control information retained within the hub terminal is updated.However, there has been no means of reflecting the updated controlinformation back to a new hub terminal should the hub terminal bechanged for some reason. If that happens, the network cannot bemaintained.

SUMMARY OF THE INVENTION

[0005] To solve the above-mentioned problem, the present inventionprovides a procedure for selecting a terminal mode for allowing acommunication device to be consfigured as a hub terminal or a leafterminal, a procedure for initially registering a communication devicein a network, an association procedure for giving permission for acommunication device to communicate in the network, a means of creatingor updating registered station information indicating the communicationdevices forming the network, and a means of synchronizing the registeredstation information among the communication devices.

[0006] Specifically, the invention provides a method of managing acommunication network formed by a plurality of registered communicationdevices that are identified by unique IDs, with each communicationnetwork being identified by a network ID. Communication devices thatacquired station IDs in a communication network communicate with oneanother. Of the communication devices that acquired the station IDs, onecommunication device constitutes a hub terminal, with the othercommunication devices constituting leaf terminals. The hub terminaltransmits network management information periodically that includesinformation about the network ID and the assignment of station IDs. Theleaf terminals, on the other hand, transmit terminal synchronizinginformation periodically in accordance with the network managementinformation. The communication device according to the present inventionis a communication device in the above communication network managementinformation. The communication device comprises a memory means forretaining the network ID of a network in which the communication deviceparticipates, a means of determining whether or not a communicationchannel is occupied by sensing the carrier, and a detection means fordetecting network management information including the network ID whichis retained by the communication device.

[0007] This application includes part or all of the contents asdisclosed in the specification and/or drawings of JP Patent ApplicationNos. 2000-192211 and 2000-260301, which are priority documents of thepresent application.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008]FIG. 1 shows an example of a communication network according to anembodiment of the invention.

[0009]FIG. 2 shows an example of a transmission signal in thecommunication network according to the embodiment of the invention.

[0010]FIG. 3 shows an example of the procedure for selecting theterminal mode according to the embodiment of the invention.

[0011]FIG. 4 shows an example of the configuration of a communicationdevice according to the embodiment of the invention.

[0012]FIG. 5 shows another example of the configuration of thecommunication device according to the embodiment of the invention.

[0013]FIG. 6 shows an example of a dedicated leaf terminal, which is theminimum configuration of the communication device according to theembodiment of the invention.

[0014]FIG. 7 shows an example of the procedure for initial registrationaccording to the embodiment of the invention.

[0015]FIG. 8 shows an example of an association procedure to beconducted by the leaf terminal according to the embodiment of theinvention.

[0016]FIG. 9 shows an example of an association procedure to beconducted by the hub terminal according to the embodiment of theinvention.

[0017]FIG. 10 shows an example of a procedure for supplementingregistered station information according to the embodiment of theinvention.

[0018]FIG. 11 shows an example of a procedure to be conducted by aregistered-station information synchronizing party according to theembodiment of the invention.

[0019]FIG. 12 shows an example of a procedure to be conducted by aregistered station information receiving party.

[0020]FIG. 13 shows an example of the configuration of a communicationdevice whose performance can be varied as desired according to theembodiment of the invention.

[0021]FIG. 14 shows an example of the registered station informationretained by a hub-capable terminal according to the embodiment of theinvention.

[0022]FIG. 15 shows an example of a procedure to be conducted by thehub-capable terminal having registered station information in responseto an association request from a leaf terminal.

[0023]FIG. 16 shows an example of a procedure to be conducted by areferencing party during the process of synchronizing the registeredstation information according to the embodiment of the invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0024]FIG. 1 shows an example of a communication network according to anembodiment of the invention.

[0025] The network of FIG. 1 comprises a communication device configuredas a hub terminal, and three other communication devices configured asleaf terminals. The communication devices communicate with one another.

[0026]FIG. 2 shows an example of a transmission signal in the network ofFIG. 1. The signal comprises network management information transmittedby the hub terminal periodically, terminal synchronization informationfrom each leaf terminal, followed by data transmitted by each terminal.

[0027] The network management information includes a network ID retainedby the hub terminal, station ID information indicating whether or notthe station ID for the network is being used, and a request fortransmitting the terminal synchronization information which specifiesthe leaf terminal that should a terminal synchronizing signal. The leafterminal specified in the request for transmission of the terminalsynchronization information transmits its own terminal synchronizationinformation following the network management information.

[0028]FIG. 4 shows a functional diagram of a communication device in theembodiment of the invention. The communication device recited in claim 2comprises a carrier-sensing unit 1203, a network management informationdetection unit 1204, and a network ID retaining unit 1205. Thecommunication device is capable of detecting the network in which itparticipates.

[0029] A communication device recited in claim 4 comprises a terminalsynchronization information generating unit 1206, in addition to theabove. The communication device is capable of transmitting the terminalsynchronization information in response to the network managementinformation and operating as a leaf terminal.

[0030] A communication device recited in claim 5 further comprises aregistered station information retaining unit 1209, a unique IDsearch/comparison unit 1210, and a unique ID addition unit 1211. Thecommunication device is capable of managing a list of unique IDs foreach of the communication devices that retains the same network ID asits own network ID.

[0031] A communication device recited in claim 6 further comprises, inaddition to the above configuration, a network management informationgenerating unit 1208, and a station ID management unit 1207. Thecommunication device is capable of initial registration, responding toassociation, and operating as a hub terminal by transmitting networkmanagement information.

[0032] A communication device according to claim 10 comprises a networkID retaining unit 1205 and an initializing unit 1212 for initializingthe contents of the registered station-information retaining unit 1209.This communication device is capable of initializing anothercommunication device, one that is already registered in a network, sothat it can be initially registered in a new network.

[0033] A communication device according to claims 18 and 19 may comprisea network ID retaining unit 1205 or a combination of that unit and ancorresponding registered station information retaining unit 1209 in theform of another state retaining unit 1213. Under certain circumstances,the communication device may retain more combinations of states.

[0034]FIG. 5 shows another functional diagram of a communication deviceaccording to another embodiment of the invention. The communicationdevice according to claims 4, 6 and 10 comprises a receiver unit B01 forreceiving a signal on a communication channel, a carrier-sensing unitB02 for determining whether or not the communication channel is beingused, a transmission unit B03 for transmitting a signal onto thecommunication channel, a message reception/generation unit B04 forreceiving a message or generating a message to be transmitted, a dataretaining unit B05 for storing data required by the communicationdevice, and a control unit B06 for conducting communications in anetwork.

[0035] The message reception/generation unit B04 receives or generatesmessages relating to network management information A07, terminalsynchronization information A08, registration request/response A09,association request/response A10, and registered station informationreference/acknowledgement/response A11. The data-retaining unit B05 hasregions for retaining a network ID A12, a unique ID A13, a station IDA14, registered station information A15, and a checksum A16. The controlunit B06 has the function of performing station ID management A17,unique ID search/addition A18, registered station informationsynchronization A19, a hub terminal selection procedure A20, an initialregistration procedure A21, and an association procedure A22.

[0036] In its initial state, the communication device has network ID A12with a value indicating that the device does not yet belong to anynetwork, or it has a unique value for each communication device, whichmay be identical to the value of the unique ID A13 of the communicationdevice.

[0037] Once the communication device is activated, a carrier-sensingprocess is performed (S301) by the carrier-sensing unit 1203 accordingto the terminal mode selection procedure shown in FIG. 3, in order todetermine if the network ID A12 agrees with that in the networkmanagement information A07 based on a signal on the channel that isbeing used (S302).

[0038] If agreement in the network IDs is detected (S303), it means thatthere is already a network, so that the communication device isconfigured as a leaf terminal (S304).

[0039] If no agreement in the network IDs is detected after making around of the channel being used, this process is repeated a randomnumber of times (S305). If the random number is completed, thecommunication device determines that there is no hub terminal having thenetwork ID A12 and configures itself as a hub terminal (S306).

[0040] The communication device configured as the hub terminal startssending network management information on a channel that was not beingused during the carrier-sensing process. Instead of determining therepetition of random numbers (S305), the end of the repetition may bedetermined based on a certain probability before the communicationdevice is configured as a hub terminal (S306).

[0041] The communication device may be a dedicated leaf terminals thatcannot be configured as a hub terminal. FIG. 6 shows a diagram of such acommunication device.

[0042] In the communication device specialized to be a leaf terminal, ascan be seen from a message reception/generation unit L04, a dataretaining unit L05 and a control unit L06 in FIG. 6, the functionsrelating to the registered station information and the function ofcontrolling the station ID are omitted. This is in contrast to thecommunication device of FIG. 5. Further, because the communicationdevice in this case cannot constitute a hub terminal, the procedure ofFIG. 3 is modified such that the step S305 of selecting the terminalmode always returns back to step S301.

[0043] The communication device in an initial state is always configuredas a hub terminal because it has a unique station ID. Accordingly, ifsuch a communication device is to newly participate in a network, it isinitially registered with respect to the communication devices operatingin the network through an initial registration procedure A21 as shown inFIG. 7.

[0044] During initial registration, the communication device to beregistered, that is the registration requesting party (S601) and thecommunication devices operating in the network, that is the registrationresponding party (S606) are set to a registration mode.

[0045] The communication devices on the registration responding partyare temporarily removed from the network when they are set to theregistration mode, so that they are unable to communicate withcommunication devices other than the one that is to be initiallyregistered. The requesting party transmits to the responding party aregistration requesting message including the unique ID A13 held in itsown data retaining unit B05 (S602), and waits for the arrival of aregistration response message (S603).

[0046] Upon reception of the requesting message (S607), the respondingparty incorporates the requesting party's unique ID, which is in theregistration requesting message, provided that the unique ID is notpresent in the registered station information (S608). It then transmitsa registration response message to the requesting party (S609), andreleases the registration mode (S610).

[0047] Upon reception of the registration response message, therequesting party retains the network ID that exists in the registrationresponse message in the network ID A12 of its own data-retaining unitB05.

[0048] The two communication devices that were set to the registrationmode during the initial registration process are again subjected to theterminal mode selection process after the registration mode is released.

[0049] When there is more than one communication device having theidentical network ID as a result of initial registration, normally thecommunication device that was activated first is configured as the hubterminal. Thus, the communication devices that were subsequentlyactivated can detect the network management information transmitted bythe hub terminal and are therefore configured as leaf terminals.

[0050] Each of the communication devices configured as leaf terminalsperforms an association process with respect to the hub terminal andafter a station ID for each communication device is determined, thecommunication devices can communicate with one another in the network.

[0051] In an association procedure shown in FIG. 8, a leaf terminalselects an unused station ID by referring to the network controlinformation transmitted by the hub terminal (S701). The leaf terminalthen transmits an association request including the selected station IDand its own unique ID to the hub terminal (S702). The leaf terminalactivates an association timer (S703), and waits for the arrival of anassociation response message from the hub terminal (S704) until thetime-out of the association timer (S705).

[0052] If the leaf terminal receives the association response messagebefore the time-out, the association process is successful, so that theleaf terminal can communicate in the network using the selected stationID. If the leaf terminal fails to receive the association responsemessage before the time-out, association is unsuccessful and the leafterminal cannot communicate in the network.

[0053] Upon reception of the association request message from the leafterminal (S801), the hub terminal checks to see if the unique ID in themessage exists in the registered station information that is beingretained in the hub terminal (S802). If it does, this means that theleaf terminal is an initially registered communication device, so thatthe hub station grants association, switches the selected station ID to“being used” (S803), and transmits an association response message tothe leaf terminal (S805). If the unique ID is not present in theregistered station information, the hub station refuses association(S804), and the association procedure comes to an end.

[0054] The leaf terminal that successfully accomplished associationfirst synchronizes the registered station information with the hubterminal such that the contents of the registered station informationretained by both the hub terminal and the leaf terminal are identical.

[0055]FIG. 11 shows an example of the procedure to be performed by theparty initiating the synchronization of the registered stationinformation is initiated. According to this procedure, the leaf terminaltransmits a registered station information-acknowledging message,including the checksum of its own registered station information, to thehub terminal (S1001).

[0056] Upon reception of the registered stationinformation-acknowledging message (S1101), the hub terminal compares thechecksum in the message with its own checksum (S1102), according to theprocedure shown in FIG. 12 for the registered station informationsynchronization receiving party. If both of the checksums agree witheach other, the individual pieces of registered station information areidentical, so the hub terminal transmits a registered stationinformation response message including its own checksum to the leafterminal (S1104).

[0057] If the checksums did not agree in step S1102, the hub terminalsupplements the registered station information for the leaf terminal(S1103).

[0058]FIG. 10 shows an example of the procedure for supplementing theregistered station information. The hub terminal, that is the registeredstation information referencing party, transmits a registered stationinformation reference message to the leaf terminal (S901). Uponreception of the registered station information reference message(S905), the leaf terminal transmits its own registered stationinformation to the hub terminal, that is the referenced party (S906).

[0059] Having received the registered station information from the leafterminal (S902), the hub terminal compares it with its own registeredstation information. If there is a unique ID that is not yet registered,the hub terminal adds the unique ID to its own registered stationinformation (S903) and updates the checksum (S904).

[0060] If there is no unique ID that has not yet been registered, thechecksum of the hub terminal remains the same as before.

[0061] After the supplementation of the registered station informationis complete (S1103), the hub terminal transmits a registered stationinformation response message, which includes the updated checksum, tothe leaf terminal (S1104).

[0062] Upon reception of the registered station information responsemessage from the hub station (S1002), the leaf terminal compares thechecksum of the hub station with that of its own (S1003). If they agree,it shows that the registered station information of the hub terminal isidentical to that of the leaf terminal, and therefore the process ofsynchronizing the registered station information comes to an end. On theother hand, if the checksums do not agree, the leaf terminal conductsthe process of supplementing the registered station information for thehub terminal, thereby updating the checksum (S1004).

[0063] At this point, both the leaf terminal and the hub terminal havereceived un-registered unique IDs from each other. When the leafterminal compares the updated checksum with the checksum from the hubterminal (S1005), their individual registered station information shouldcorrespond, so that the registered station information synchronizingprocess can come to an end. However, if they do not correspond, theregistered station information synchronizing process is repeated.

[0064] When the registered station information is thus updated by theregistered station information synchronizing process initiated by theleaf terminal, the hub terminal initiates the registered stationinformation synchronizing process with respect to all of the leafterminals in the network, so that the change is reflected in all theregistered station information in the network.

[0065] If the power supply to the hub terminal is cut off in anoperating network, or if the hub terminal is set to the registrationmode for initial registration, the hub terminal vanishes from thenetwork and the leaf terminals cannot receive the network managementinformation, and so communication breaks down. But the communicationdevices terminate their operation as leaf terminals in the absence ofthe network management information for a predetermined period of time,and initiate the terminal mode selection procedure, as when they areactivated for the first time.

[0066] Even if more than one terminal initiates the terminal modeselection procedure simultaneously, the function of a new hub terminalis assumed by the communication device that detects the network first instep S305. The other communication devices detect the network managementinformation from the new hub terminal and are configured as leafterminals.

[0067] A communication device that has been set to the registration modeand ceased to be the hub terminal is configured as a leaf terminalduring the terminal mode selection if another communication device isalready configured as a hub terminal after initial registration. Theleaf terminal is therefore associated with this hub terminal and, afterassociation is complete, the leaf terminal synchronizes the registeredstation information with respect to the hub terminal. As a result, theunique ID that was added to the registered station information duringinitial registration is reflected in the registered station informationof the operating hub terminal. Further, the hub terminal, its ownregistered station information having been modified, conducts theregistered station information synchronizing process with respect to allof the leaf terminals in the network. Thus, the addition of a singleunique ID is reflected in all the registered station information in thenetwork.

[0068] In this way, the hub terminal permits a newly registeredcommunication device to perform association.

[0069] When a communication device that is already initially registeredin a network is to be registered in another network, it is necessary toinitialize the communication device by erasing the network ID andregistered station information retained therein using an initializingmeans in the communication device. This is because a communicationdevice that retains registered station information cannot requestinitial registration.

[0070] When the communication device is capable of retaining a pluralityof network IDs corresponding to the state retaining unit 1213 of FIG. 4,or groups of registered station information corresponding to the networkIDs, the communication device can be initially registered for aplurality of networks and thereby store a plurality of network IDs. Byassociating the communication device with each of the networks, thecommunication device can communicate in the multiple networkssimultaneously or alternately by switching. If the communication deviceretains the registered station information corresponding to a network IDused, the communication device can be configured as a hub terminal inthe particular network.

[0071]FIG. 13 shows an example of a communication device whoseperformance in communication network operation can be varied.Performance items for a communication device include the communicationspeed at which transmission and reception can occur, modulation method,the encoding method which allows for encoding and decoding, and the typeof application. To display a history of updates, real-time clock timestamp or a counter value that is updated for each change in performanceinformation may be used. A communication device with a performancemodification means has it's program modified from the outside. When thecommunication device is capable of selecting its own performance, aparticular level of performance is selected by a switch, or theperformance is modified by the addition of a device supplementary to thecommunication device. Such modification in performance is accompanied byan updating of performance information on the communication network andan updating of a history of updates as it relates to changes inperformance.

[0072] The performance of the communication device is defined withrespect to the communication network in which it participates, namelythe network ID the communication device retains internally. Accordingly,in a communication device retaining a plurality of network IDs, itshistory information is also updated each time a change in performanceoccurs in any of the networks whose network IDs the communication devicepossesses.

[0073] In a network having the communication device whose performancecan be varied, the registered station information retained by a terminalconfigured as the hub can be defined as shown in FIG. 14. In this case,in step S602 of the procedure of FIG. 7a, the initial registrationrequesting party transmits a registration request message includingperformance and history information as well as the unique ID. In stepS608 of the procedure of FIG. 7b, the initial registration respondingparty adds the performance and history information as well as the uniqueID to the registered station information.

[0074] In step S702 for the association of a leaf terminal, as shown inFIG. 8, the leaf terminal transmits an association request messageincluding performance and history information as well as a selectedstation ID and its own unique ID.

[0075]FIG. 15 shows the operation procedure to be performed by thehub-capable terminal having the registered station information of FIG.14 operating as the hub terminal in response to the association requestfrom the leaf terminal. Upon reception of the association request fromthe leaf terminal (S1501), the hub terminal checks to see if the uniqueID in the message is present in its own registered station information(S1502). If not, the hub terminal rejects association (S1504), and theassociation procedure comes to an end. If the unique ID exists in theretained registered station information, this means that the leafterminal that transmitted the association request is a communicationdevice that is already initially registered. Thus, the hub terminalgrants association, and then compares its history information with thatin the registered station information (S1503). If there is adiscrepancy, the hub terminal updates the performance and historyinformation that exist in its own registered station information to thevalues existing in the association request message. Further, the hubstation changes the selected station ID to “being used” (S1505), andtransmits an association response message to the leaf terminal (S1506).

[0076] When the registered station information is modified by theassociation operation, the hub terminal performs an operation forsynchronizing the registered station information with the otherhub-capable terminals. Accordingly, a modification of performanceinformation can immediately be reflected when a communication deviceparticipates in a communication network.

[0077]FIG. 16 shows the procedure to be performed on the referencingparty in the operation for synchronizing the registered stationinformation. First, the referencing party transmits a registered stationinformation reference message to the referenced party (S1601). Uponreception of registered station information from the referred terminals(S1602), the referencing party compares the received information withthe registered station information of its own. If an un-registeredunique ID exists, the referencing party adds that to its own registeredstation information together with the performance and historyinformation (S1603). The referencing party further compares the historyinformation about the unique ID that is already registered. If its ownhistory information is older, the referencing party replaces its ownperformance and history information of the relevant unique ID with thecontents received from the referenced party (S1604), and updates thechecksum (S1605).

[0078] All publications, patents and patent applications cited hereinare incorporated herein by reference in their entirety.

INDUSTRIAL APPLICABILITY

[0079] The present invention provides useful means of modifying theterminal configuration in a network.

1. A method of managing a communication network formed by a plurality ofregistered communication devices that are identified by unique IDs, witheach network being identified by a network ID, wherein communicationdevices that acquired station IDs in a single communication networkcommunicate with one another, wherein of the communication devices thatacquired the station IDs, one constitutes a hub terminal while the othercommunication devices constitute leaf terminals, wherein the hubterminal periodically transmits network management information includingthe network ID and information about the assignment of the station IDs,the leaf terminals periodically transmitting terminal synchronizationinformation in accordance with the network management information. 2.The communication device according to claim 1, comprising a storagemeans for retaining the network ID of a communication network in whichthe communication device participates, means of determining, through acarrier sense operation, whether or not a communication channel is beingused, and a detection means for detecting network management informationincluding the network ID of the communication device.
 3. A method ofmanaging a communication network, in which the communication deviceaccording to claim 2 performs the carrier-sensing operation and detects,on the communication channel being used, the network managementinformation including the network ID which is retained by thecommunication device.
 4. The communication device according to claim 3,further comprising means of transmitting terminal synchronizationinformation in accordance with the network management information,whereby the communication device can operate as a leaf terminal.
 5. Thecommunication device according to claim 4, further comprising means formanaging the use/non-use of the station ID, and means for transmittingthe network management information, so that the communication device canoperate as a hub terminal.
 6. The communication device according toclaim 5, further comprising a storage means for storing, as registeredstation information, a list of unique IDs of communication deviceshaving a network ID which is identical to the network ID of thecommunication device, means for determining whether a certain unique IDexists in the registered station information, and means for adding aunique ID newly to the registered station information.
 7. A method ofmanaging a communication network which comprises a procedure forselecting a hub terminal in a communication network, in which thecommunication device according to claim 6 repeats the process ofdetecting the communication network a random number of times inaccordance with the method of claim 3, wherein if the network isdetected during the detection process, the communication device operatesas a leaf terminal and if not and if the communication device canoperate as a hub terminal, the communication device transmits networkmanagement information over a vacant communication channel, so that thecommunication device is configured to operate as a hub terminal of thenetwork whose network ID is retained by the communication device.
 8. Amethod of managing a communication network which comprises an initialregistration procedure for newly registering a communication device in acommunication network, in which a new communication device according toany one of claims 4 to 6, that is the initial registration requestingparty, transmits a registration request message including the unique IDof its own to an existing communication device, wherein upon receptionof the registration request message, the responding party in the initialregistration process adds the unique ID in the message if the unique IDdoes not exist in its own registered station information, and transmitsa registration response message including its own network ID to therequesting party, wherein the requesting party receives the registrationresponse message and retains the network ID in the message as its ownnetwork ID.
 9. A method of managing a communication network, in whichthe communication device according to claim 4 or 6 comprises means forsetting itself to a registration mode for performing the initialregistration procedure, wherein only those communication devices thatare set to the registration mode perform the initial registrationoperation.
 10. The communication device according to claim 6, furthercomprising means for erasing the retained network ID and correspondingregistered station information, so that the communication device can bebrought back to the initial state.
 11. A method of managing acommunication network, in which the communication device according toclaim 6 is prohibited from being initially registered when theregistered station information in the communication device is not in aninitial state.
 12. A method of managing a network comprising means ofassociation for allowing a communication device to obtain a station IDfor communicating in a network, wherein the communication deviceaccording to claim 4 or 6 comprises means for monitoring networkmanagement information to be transmitted by a hub terminal periodically,and an association timer, wherein the communication device detects anun-used station ID from the network management information, transmits anassociation request message including its own unique ID and the un-usedstation ID to the hub terminal, wherein the hub terminal changes thestatus of the station ID designated by the association request messagefrom un-used to used if, in light of the contents of the associationrequest message, the unique ID of the communication device exists in theregistered station information, and transmits an association responsemessage to the communication device that transmitted the associationrequest message, wherein the terminal which transmitted the associationrequest commences communication as a leaf terminal by using the acquiredstation ID only when the terminal received the association responsemessage from the hub terminal.
 13. A method of managing a network,wherein, when the communication device according to claim 6 operates asthe hub terminal, the method comprises means for monitoring terminalsynchronization information transmitted by a leaf terminal having astation ID that is being used, wherein the status of the assignedstation ID is changed to un-used when terminal information from theparticular leaf terminal is not recognized for a certain duration oftime.
 14. A method of managing a network which comprises a procedure forsupplementing the registered station information among communicationdevices, wherein the communication device according to claim 6 comprisesmeans for transmitting registered station information reference message,means for transmitting registered station information, and means forcomparing registered station information that is received with theregistered station information in the communication device, wherein areferencing party transmits a registered station information referencemessage to a referenced party, wherein the referenced party, uponreception of the registered station information reference message,transmits its own registered station information to the referring party,wherein the referring party, upon reception of the registered stationinformation of the referenced party, compares it with its own registeredstation information and adds to its own registered station informationand retains therein a unique ID that is included in the receivedregistered station information but which is not included in its ownregistered station information.
 15. A method of a managing network whichcomprises a procedure for synchronizing registered station informationamong communication devices, wherein the communication device accordingto claim 6 comprises means for generating a checksum of its ownregistered station information, means for transmitting a registeredstation information acknowledging message including the checksum and aregistered station information response message to other communicationdevices in the network, and means for comparing a checksum that isreceived with the checksum of its own, wherein a synchronizationinitiating party transmits a registered station informationacknowledging message to a synchronized party, receives a registeredstation information response message therefrom, and compares thechecksum of the synchronized party with the checksum of its own, whereinthe synchronization operation comes to an end if the checksumscorrespond, otherwise the synchronizing party supplements the registeredstation information of the synchronized party by the means according toclaim 15 and again transmits a registered station informationacknowledging message to the synchronized party, wherein this procedureis repeated until the checksum of the synchronized party agrees with thechecksum of its own, wherein the synchronized party compares thechecksum included in the registered station information acknowledgingmessage from the synchronization initiating party with the checksum ofits own, and transmits a registered station information response messageto the synchronization initiating party when they correspond, otherwisethe synchronized party supplements the registered station information ofthe synchronization-initiating party and then transmits a registeredstation information response message to the synchronization-initiatingparty.
 16. A method of managing a communication network, wherein a leafterminal which successfully achieved association synchronizes registeredstation information with a hub terminal.
 17. A method of managing acommunication network which comprises a procedure for synchronizingregistered station information of all of the communication devicescommunicating in a network, wherein a hub terminal whose registeredstation information has been modified performs a registered stationinformation synchronization operation with all of the other leafterminals sequentially.
 18. The communication device according to claim4 or 6, further comprising means for retaining a plurality of networkIDs.
 19. The communication device according to claim 6, furthercomprising means for retaining registered station informationcorresponding to each of a plurality of network IDs.
 20. A method ofmanaging a communication network, wherein the initial registrationaccording to claim 8 is performed with respect to a plurality ofcommunication networks, so that the communication device is operable ina plurality of networks.
 21. A communication device comprising anupdating means for varying the performance of the communication deviceas desired, and means for retaining history information about changes inits own performance, wherein the history information is updated when theperformance is varied.
 22. A method of managing a network, wherein theunique ID of the communication device, corresponding performanceinformation and its history information are stored in the registeredstation information according to claim
 6. 23. A method of managing anetwork, wherein, during the association procedure according to claim12, the hub terminal confirms the performance information of acommunication device requesting association, and updates its ownregistered station information if there is any difference between itsown performance information and the contents of the registered stationinformation.
 24. A method of managing a network, wherein, during theregistered station information synchronizing procedure by the meansaccording to claim 17, when there is any difference in the performanceinformation with regard to the registered unique ID, the performanceinformation is updated in accordance with the newer information bycomparing history information.